The metabolic strategy of phosphorus-accumulating organisms in response to low temperature in micro pressure swirl reactor

The impact of low temperature on the growth and metabolism of phosphorus-accumulating organisms (PAO) is crucial for maintaining the stability of organic removal efficiency. To investigate how lowering the temperature affects PAO's metabolic strategy, a micro pressure swirl reactor (MPSR) was operated at temperatures of 15, 12, and 10 degrees C. The interactions and metabolic pathways of the microbial community in the system were examined. The results showed total phosphorus (TP) removal rate efficiencies were 97.0%, 94.0%, and 94.8% in 15, 12 and 10 degrees C, respectively. As the temperature decreased, glycogen consumption decreased by 27.44 mg/gMLSS, while poly-(3-hydroxybutyrate (PHB) accumulation and consumption increased by 33.80 and 37.88 mg/gMLSS, respectively. Two essential genera of PAO, Rhodocyclus, and Dechloromonas increased from 0.70 % and 0.31-3.04 % and 2.79% respectively. The metabolism of PAO changed as the temperature decreased. Glycolysis was inhibited at temperatures 12 and 10 degrees C, and PAO applied an increase in phosphorus metabolism to meet the energy requirements for growth metabolism. This conversion in metabolic strategy helped PAO gain a competitive advantage and ensured that MPSR maintained good phosphorus organic matter removal at low temperatures.